Can't open PDF without embedded font list

[hjele]

We recently discovered that we can't open a PDF, which does not contain a embedded font list. As there are some after OCR.
In this case we get the following message:
PDF.js Version 1.4.20 (build: b15f335) Nachricht: Cannot read properties of undefined (reading 'get') Aufrufliste: TypeError: Cannot read properties of undefined (reading 'get') at Parser.Parser_makeFilter [as makeFilter] (https://ubdocs.aau.at/pdfjs/build/pdf.worker.js:21982:23) at Parser.Parser_filter [as filter] (https://ubdocs.aau.at/pdfjs/build/pdf.worker.js:21974:25) at Parser.Parser_makeStream [as makeStream] (https://ubdocs.aau.at/pdfjs/build/pdf.worker.js:21949:21) at Parser.Parser_getObj [as getObj] (https://ubdocs.aau.at/pdfjs/build/pdf.worker.js:21568:28) at XRef.XRef_fetchUncompressed [as fetchUncompressed] (https://ubdocs.aau.at/pdfjs/build/pdf.worker.js:24662:28) at XRef.XRef_fetch [as fetch] (https://ubdocs.aau.at/pdfjs/build/pdf.worker.js:24619:26) at ObjectLoader.ObjectLoader_walk [as _walk] (https://ubdocs.aau.at/pdfjs/build/pdf.worker.js:25068:37) at ObjectLoader.ObjectLoader_load [as load] (https://ubdocs.aau.at/pdfjs/build/pdf.worker.js:25048:12) at Page.resourceSuccess (https://ubdocs.aau.at/pdfjs/build/pdf.worker.js:40750:29) at async Promise.all (index 1)
Is this well known?

See this two examples:

1. Does not work
   https://ubdocs.aau.at/pdfjs/web/viewer.html?file=https://ubdocs.aau.at/open/voll/altbestand/AC02139228_1860_5.pdf
2. Does well:
   https://ubdocs.aau.at/pdfjs/web/viewer.html?file=https://ubdocs.aau.at/open/voll/altbestand/AC00044608.pdf

[Snuffleupagus]

PDF.js Version 1.4.20 (build: b15f335)

That version is no longer supported, since it's nine years old; please find the latest releases at https://mozilla.github.io/pdf.js/getting_started/#download

When updating, please keep the following in mind http://mozilla.github.io/pdf.js/getting_started/#introduction (emphasis mine):

The viewer is built on the display layer and is the UI for PDF viewer in Firefox and the other browser extensions within the project. It can be a good starting point for building your own viewer. However, we do ask if you plan to embed the viewer in your own site, that it not just be an unmodified version. Please re-skin it or build upon it.